The invention relates to medical aids for supporting the function of the knee joint, in particular to knee-joint orthoses with a pad engaging around the patella of the knee joint. The invention makes available an improved patellar pad which has the additional function of supporting movement and has additional preventive/therapeutic functions.
Knee-joint orthoses are known with an annular or semi-annular pad cushion that encloses the patella of the knee joint when the orthosis is fitted in place. As is known, such orthoses can be designed as stocking-like or hose-like elastic knits. In the area of the patella, a pad is fitted in the knit. The pad supports the patella and fixes the latter in the physiologically correct position in the joint, in particular in conjunction with the pressure conferred by the elastic knit. Known pads are made from an elastic material such as silicone rubber or polyurethane or similar materials.
Below the knee joint, particularly in the anterior compartment of the knee, an infrapatellar fat body, or Hoffa's fat pad, lies to both sides of the knee cap. Under certain physiological and hormonal conditions, hyperplasia of the fat body takes place and, in some cases, hypotrophy with permanent replacement of the fat cells by collagenous connective tissue. When bending and extending the knee in such cases, there is a significant increase in pressure in the fat body, which is associated with painful and restricted movement. In the healthy organism, the infrapatellar fat body serves to support the joint function by primarily filling volumes in the joint interstices, in order to ensure a completely congruent closure in every movement state between the joint elements of tibia, femur and patella, particularly the femoral condyles, the anterior horns of the meniscus, and the tibial plateau. The infrapatellar fat body is also ascribed the role of soft-tissue embedding of tendons, particularly the patellar tendon, for stabilizing the patella in the extension position, and of mechanically damping the load transfer and positioning the patella. Certain conditions can involve a reduction in volume and atrophy of the fat bodies. The supporting function is then no longer ensured. In addition, the infrapatellar fat bodies are also directly implicated in the development of pain in the knee joint. Tests show that the fat bodies themselves are innervated with pressure sensors and pain-conducting fibers.
The object of the invention is to extend the field of use of knee-joint bandages and orthoses of the type in question, with an inserted patellar pad, such that pathological states connected with the infrapatellar fat body of the knee joint, in particular pain and restricted movements, can be treated preventively and therapeutically.